Job page UI trigger variables missing, when using Web

Summary

The Jobs page contains Trigger Variables, when a pipeline is triggered using the API.

It might be reasonable to expect manually/web triggered pipelines to contain those same variables, but they're missing.

I'm not sure this is supported, so I've omitted the bug tag.

Steps to reproduce

  1. Create a new project with at least 1 job step (I'm using Powershell on a Windows build runner), or the equivalent Linux. It's not material to the issue:
//.gitlab-ci.yaml
build:
  script:
  - |
    Write-Host "Triggered with CI_PIPELINE_SOURCE='$($env:CI_PIPELINE_SOURCE)' by $($env:GITLAB_USER_EMAIL)"
    Write-Host "PACKAGE_VERSION='$($env:PACKAGE_VERSION)'"
  1. Trigger a build (Generate a build token on settings/ci_cd >> pipeline triggers)
curl -s -X POST \
 -F token=$token \
 -F 'ref=master' \
 -F 'variables[PACKAGE_VERSION]=10.0.4.20200403'
 https://gitlab.com/api/v4/projects/18333581/trigger/pipeline
  1. Navigate to the jobs page, observe trigger variables on right-hand-side track. The job output should look similar to:
Triggered with CI_PIPELINE_SOURCE='trigger' by carl.brown194@t-mobile.com
PACKAGE_VERSION='10.0.4.20200430'

  1. Trigger a new pipeline via web, ensure at least 1 variable added (/cbrown194/hello-sched-pipelines/pipelines/new).

  2. Navigate to the jobs page, observe there are NO variables listed on right-hand-side track. The job output should look similar to:

Triggered with CI_PIPELINE_SOURCE='web' by carl.brown194@t-mobile.com
PACKAGE_VERSION='10.0.4.20200430'

Example Project

I have a working example at https://gitlab.com/cbrown194/hello-sched-pipelines . Ping me via Gitlab or carl.brown194@t-mobile.com and I can add people who are triaging; however, I shouldn't make this public as I have a pet runner I've been using.

Repro: 3. API-triggered: https://gitlab.com/cbrown194/hello-sched-pipelines/-/jobs/526398875

Lines 22-26 VERBOSE: BoundVariables { ...json...} show the inputted variables (via cUrl).

trigger-job

  1. Web-triggered: https://gitlab.com/cbrown194/hello-sched-pipelines/-/jobs/526408565

Lines 23-27 VERBOSE: BoundVariables { ...json...} show the inputted variables (entered via Web).

web-job

What is the current bug behavior?

When a pipeline is triggered via Web UI, no pipeline variables are observable on the jobs page.

What is the expected correct behavior?

When a pipeline is triggered, regardless of via API or Web UI, pipeline variables are observable on the jobs page.